Synergistic Regulation of Piezoelectric-Pyroelectric Multifunctionality in Bi_0.5Na_0.5TiO₃ (BNT) Ceramics via...

Area of Science:

• Materials Science
• Solid State Chemistry
• Ceramics Engineering

Background:

• Bismuth sodium titanate (Bi_0.5Na_0.5TiO₃, BNT) is a lead-free perovskite with promising piezoelectric and pyroelectric properties.
• Its practical application is limited by a low depolarization temperature (T_d), hindering high-temperature performance.
• Conventional doping strategies often face trade-offs between piezoelectric and pyroelectric properties.

Purpose of the Study:

• To investigate the effect of high-entropy engineering on the piezoelectric and pyroelectric properties of BNT-based ceramics.
• To enhance the polarization thermal stability and depolarization temperature of lead-free BNT ceramics.
• To develop a strategy for creating multifunctional lead-free ceramics for high-temperature applications.

Main Methods:

• Synthesis of a (1-x)Bi_0.5Na_0.5TiO₃-x(Bi_1/6Na_1/6Ba_1/6Sr_1/6Mg_1/6Zn_1/6TiO₃) ceramic system using high-entropy engineering.
• Introduction of multicomponent A-site configurations to induce lattice distortion and local disorder.
• Characterization of structural, piezoelectric, and pyroelectric properties, including depolarization temperature (T_d), piezoelectric coefficient (d₃₃), and mechanical quality factor (Q_m).

Main Results:

• High-entropy engineering effectively modulated lattice distortion and local disorder.
• The sample with x = 0.15 showed enhanced polarization stability, maintaining d₃₃ ≈ 80 pC/N, with T_d = 182 °C and Q_m = 1036.
• The sample with x = 0.05 exhibited optimal pyroelectric performance with T_d = 176 °C, F_v = 3.24 × 10^-2 m²/C, and a piezoelectric activity quality factor of 1658 × 10^-15 m²/N.

Conclusions:

• High-entropy engineering offers a viable approach to overcome conventional doping limitations in lead-free BNT ceramics.
• This strategy synergistically enhances both piezoelectric and pyroelectric responses while improving thermal stability.
• The developed lead-free multifunctional ceramics are suitable for high-temperature applications.